How to mention Author in Slack via Argo CD Notifications

[siansiansu]

I've set up the Argo CD Notifications, but I have no idea how to mention commit author in the Slack message.
Here is my part of the setup for tagging author

{
    "type": "mrkdwn",
    "text": "*Author:*\n<@{{(call .repo.GetCommitMetadata .app.status.sync.revision).Author}}>"
},

As you see, it's always shows the text only. Is any a way to mention person in the Slack?